Rotary milling-cutter.



0. G. SIMMONS ROTARY MILLING CUTTER. APPLICATION FILED MAR. 13, 1913.

Ru ML N/m 6 2% m m d m E 0 m m4 .w a P. M W U M w O. G. SIMMONS.

ROTARY MILLING CUTTER.

APPLICATION FILED MAR.13,1913.

L126 w7n Patented Jan. 26, 1915.

4 SHEETS-SHEET 2.

//6Z I;T

, WITNESSES /4 j I my TOR 0//i 6/" 560/" e 2070/25 I W //e //cZ M y 5g 4Hf (4% 3 Q9 ATTORNEYS O. G. SIMMONS. ROTARY MILLING CUTTER.

Amen/5V8 O. G. SIMMONS. ROTARY MILLING CUTTER. APPLICATION FILED MAR.13,1913.

1,126,107. Patent e01 Jan.26,1915

lUTOlM/EVS UNITED STATES PATENT OFFICE.

OLIVER GEORGE SIHIMONS, OF NARIBERTH, PENNSYLVANIA, ASSIGNOR T0 WI l1 F.FISCHER, 0F PHILADELPHIA, PENNSYLVANIA.

ROTARY MILLING CUTTER.

Specification of Letters Patent.

Application filed March 13, 1913. Serial No. 753,977.,

To all whom it may concern Be it known that I, OLIVER GEORGE SIM- MONS,"a citizen of the United States, and a resident of Narberth, in thecounty of Montgomery and State of Pennsylvania, have invented a new andImproved Rotary Milling-Cutter, of which the following is a full, clear,and exact description.

This invention relates to metal Working machinery, and has particularreference to milling cutters adapted especially for use on rotarspindles, such spindles occupying substantially fixed axes.

Among the objects of this invention is to produce a milling cutterhaving peculiarly arranged teeth whereby I am enabled to form under-cutgrooves in the work.

The foregoing and many other objects of the invention are accomplishedby means hereinafter more fully described and claimed and illustrated inthe accompanying drawings, in which:

Figure 1 is a perspective view of one form of rotary cutter; Fig. 2 is abottom plan view of the same; Fig. 3 is a side elevation of the same;Figs. 4, 5 and 6 are transverse sections on the corresponding lines ofFig. 2, showin respectivel the cutting faces of the first time teeth 0the cutter; Fig. 7 1s a development of the cutter corresponding to Fig.3 and indicating diagrammatically the relative depths of the teeth andshowing their stepped arrangement; Fig. 8 is a diagram complemental toFig. 7 and showing the relative variable depths of the cuts of therespective teeth, each to each, viewed in vertical projection from Fig.7; Fig. 1s a transverse section on the line 9-9, Fig. 2, showing thecontour or outline of the deepest cutting teeth of the series, andshowing also in dotted lines the relative depths of the shallower teeth;Fig. 10 is a perspective view of another form of invention, this figurecorresponding to Fig. 1; Fig. 11 1s a side elevation of the same; Fig.12 is a bottom plan view of the same, corresponding to Fig. 2; Fig. 12isa fragmentary view of the three adjacent teeth of Fig. 12, the v ew inthis figure being taken directly 1n line with the axes of the teeth;Fig. 13 is a diagram indicating an adaptation of the invention to themaking of saw teeth; and Figs.

14, 15 and 16 are fragmentary perspective 7 views of several differentforms of teeth which may be cut by various cutters made in accordancewith this invention.

Referring more particularly to the first set of figures, I show at 10 acutter body having a series of teeth 11 arranged on one face thereof,the first cutting teeth of the series being indicated at 11, 11 and 11,and the last teeth of the series being indicated at 11. The term seriesas hereinafter used may be understood as referring to all of the teethof a cutter, but where I refer to a number of teeth which may be lessthan the entire series, I will use the word plurality.

As indicated in Figs. 4, 5, 6, 7 and 9, the bases or roots of theteethall lie in the same plane, represented at 12, and said'bases areall of the same breadth or length radially of the cutter, the essentialdifi'erence between adjacent teeth being that in depth or altitude withrespect to said base plane 12. The plane defined by said tooth base isshown as being perpendicular to the axis or center of rotation of thecutter and the teeth project therefrom in any suitable direction. Asshown in Fig. 9, the dotted and dash line 13 indicates the axis ormedian line of the teeth, such line being inclined at an oblique angleto the axis and preferably so arranged as to intersect the axis whenprojected from the lbase through the apexes or points of the teet Theteeth may be arranged in a plane, as shown, and in any suitablegeometric curve, such as in the arc of a circle or in a spiral. Thepitch of the spiral may be either single or multiple and the extent ofthe curve may be varied with respect to the distance around the axis. Inthe first set of figures the teeth are arranged in a spiral, the baseslying in said plane defining a true fiat spiral, or one in which theradii are diiferent but in which there is no displacement longitudinallyof the axis. In order for the bases of the teeth in this formof deviceto follow one another in precisely the same path through or along thework, there is caused, by an suitable mechanism, a relative movement 0the work in the direction of the radius of the cutter during therotation .of the cutter. That is to say, considering the tooth 11 asbeginning the out at'a certain radius, the work way the axis through adistance represented by the pitch of the spiral while the cutter makesone rotation.

Not onl is the axis 13 of each tooth inclined to t e axis of the cutter,but the sides of the cutting face or outline of each tooth extendingfrom the base thereofma be inclined or under cut in any desire shape.

The tooth shown in Fig. 9 is one. in whlch the outline comprises twosides, 11 and 11, both of whichare inclined to the axis of the cutterand whereby an under-cut effect of the device is produced. The apex orpoint, the part remote from the base of each tooth, may .be of anyshape, but in this form is shown as a line 11. In order to increase theeliiciency of the cutter, I provide that most of the teeth of the serieshave variably different depths, the greatest difference in depth betweenadjacent teeth being found with respect to the shallower teeth. In thisthe first cutting teeth, being stronger than the last teeth of theseries, have put upon them more work than the last teeth.

By referring to Figs. 7, 8 and 9 it will be apparent that the severalteeth difier in depth by a variable increment, the curve representingsuch variation having a shorter radius with respect to the first cuttingteeth, and finally is drawn out into a straight line with respect to thelast teeth of the series,

the last three or four teeth being of the same depth, whereby the lifeof the cutter is increased because the last cuttin tooth is reinforcedby those few that fo low directly after it completing the series. Thelast few teeth, therefore, insure a perfect finish to the work andprovide a means to cut tools such as saws, files or the like, makingperfectly smooth, keen, sharp-cut edges, which will require no furthersharpening treatment. For this reason I can produce a superior grade ofcutting tools at an exceedingly low cost.

While the bases of the teeth are shown as lying in a plane, the apexesor points thereof, as shown in Fig. 3, describe what I will term as aspiral helix was a curve which is helical with respect to displacementlongitudinally of the axis, as shown in Fig. 3, but which isspiral withrespect to the radii, as

. shown in Fig. 2.

Each tooth of the series is preferably provided with a projection '14which, like the corresponding teeth, increases in depth or altitudesubstantially in proportion to the increase in depth of the main teeth,be inning with the first teeth of the series. uch projection may betermed a roughing cutter, which, with respect to the first cuttingteeth, serves to remove any irregularities which may exist in the blankbeing worked upon and through; the operation of which the job will beturned out absolutel true. The roughing cutter extensions of t e lastteeth of the series, however as shown in Fig. 9, serve as a means tofinish a certain portion of the tool or device being cut.

It will be understood that in the practical operation of this cutterupon a straight blank, the axis of the cutter will be slightly inclinedto the plane or face of the blank, so that a portion only of the seriesof teeth will be in engagement with the work.

In Figs. 10, 11 and 12 I show a steppedtooth rotary cutter, the bases ofthe teeth not only'bemg in a plane, as before, but arranged in a arch insaid plane. The series of teeth in this modification are shown providedwith a gap 15 of any suitable width or circumferential extent allowingfor a sulficient interval between the operation of the last tooth of theseries and the beginningof the next cut by the first tooth to enable theblank to be moved a distance equal to the pitch of the spiral abovedescribed. In other words, by rotating this-cutter 10' continuallyaround a fixed axis, even though the bases of the teeth are arranged ina circle, I

can cut a succession of tool'teeth by giving 9 may be, substantially thesame in form as 9.

those of the first set of figures, but since the axes of the teeth areinclined, corresponding to the line 13 of Fig. 9, the apexes or pointsof the teeth describe a spiral helix of somewhat the same character asthat above explained. Fig. 12 indicates, though in the same exaggeratedform, the variation e in radial width of adjacent teeth and how eachtooth has an offset relation to the adjacent tooth with respect to itscutting line or point 11 The face g, of which the cutting edge 11constitutes the front edge, is bounded by inner and outer parallelcurves 16 and 16'; and the corresponding face of the next tooth is soformed as to have its parallel curved edges both closer to the me dianline of the tooth, and which lines if extended would intersect or engagethe preceding tooth within both of the first-mentioned lines 16 and 16'.In the plan views of Figs. 2 and 12, the lines 16 just referred toappear to describe a true spiral but this is because of the increase indepth of the succeeding teeth added to the inward inclination thereof.The dot-and-dash curved lines 17 of 1:

Figs. 2 and 12 indicate the fact that the curvature of each tooth aroundthe axis of the cutter when projected intersects the preceding teeth toa considerable extent within the bounding line 16 thereof. 1:

a aaaaoa this cutter within the spirit of this invention ll first make acut 18, and by the time this cut is finished the second cut 18 is begun,and so on through the first half of the operation; said cuts being ofdouble pitch enables me to change the position of the cutter with itsaxis on the opposite side of the blank 19, and then form a second seriesof cuts 18, 18, etc., leaving teeth 18 on the saw having edges 20 whichare not only at acute angles to the plane of the saw but are also hollowout, due to the curvature of the cutter. A saw made in this way requiresno filing and is of a very sharp, keen quality.

Figs. 14, 15 and 16 show various forms of teeth which may be made withrotary cutters embodying the broad principles of this invention. Fig. 14may be regarded as a fragment of a rack adapted for use in connectionwith a spiral gear. Opposing faces 21 and 22 of the teeth 23 arerespectively concave and convex and the cuts forming the spaces betweenthe teeth are made by the successive operation of a series of step edteeth the bases of which follow one anot er at the widest place betweenthe points of the teeth 21.

Figs. 15 and 16 show rounded under-cut teeth of various forms; and Fig.16 shows, also, a form of cutter 24 having a main tooth 25, which is thelast cutting tooth of the series, and an extension thereof 26*, whichforms the finish for the top of the saw toot 27 formed thereby. Y

With reference to the cutting or leading face of each cutter tooth, itw1ll be note that by the use of an ordinary cutter grinder applied tosuch face between it and the next preceding tooth, said cutter tooth mayeasily be kept sharp, and by reason of the clearance provided leadingback from the cuttin edges (shown in Fig. 9 as 161, 11, and 11 the formof each tooth remains unchanged even when round away to the maximumextent. Furt ermore, by grinding all of the teeth in succession therelative orms of all of the teeth may remain the same as the teeth of anew cutter. The lines 16 and 16 of each tooth, also, remain parallelthrough the length (circumferentially) of the tooth, by reason of theabove-stated clearance.

Having thus described my invention, 1 claim as new and desire to secureby Letters Patent:

In a rotary milling cutter, the combination of a plurality of cuttingteeth arranged in a curve around the axis of the cutter, said teethbeing of varying depths and each provided with a radially projectingauxiliary roughing cutter, the roughing cutters of the several teethalso being of varying depths.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

OLIVER GEORGE SIMMUNS.

Witnesses:

GEORGE L. Banner, PHILIP D. RoLLHAUs.

